Typically, in a medical imaging apparatus, a positioner is configured motorized for movement along various positioner axes for carrying out patient positioning and medical imaging. An electro-mechanical brake is coupled to the positioner, for holding the positioner against influence of gravity during power OFF state of the medical imaging apparatus or during an emergency situation. A control circuit comprising an electromagnetic relay, a MOSFET or a transistor device is coupled to the electro-mechanical brake. During power ON state of the medical imaging apparatus, the control circuit controls the power supplied to the electro-mechanical brake and thereby controls movement of the positioner for patient positioning and medical imaging.
Examples of a medical imaging apparatus include an X-ray apparatus, a CT scanner, a vascular imaging apparatus, etc. Examples of a positioner include a patient table, a vascular gantry comprising a C arm and a pivot axis, etc. Examples of positioner axes include lift axis, pivot, longitudinal and tilt axes.
However, with the above method and system of braking, in circumstances such as, a failure in the control circuit, especially due to an over current, a short circuit or an over voltage, the power supply to the electro-mechanical brake is not controlled. The electro-mechanical brake is likely to receive continuous power supply that may result in uncontrolled movement of the positioner especially due to influence of gravity. This uncontrolled movement of the positioner due to influence of gravity may cause shock, injury or fall of the patient from the positioner, leading to unsafe patient positioning and medical imaging.
Thus, there exists a need for a safe braking control method and system wherein the system provides for a safe and efficient braking that would not cause uncontrolled motion of the positioner due to influence of gravity, especially in circumstances such as, for example, short circuit, over current or an over voltage in the control circuit.